<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			var n1=10 , n2=20;
			var n = n1++;
			console.log('n='+n);//10
			console.log('n1='+n1);//11
			n = ++n1
			console.log('n='+n);//12
			console.log('n1='+n1);//12
			n = n2--;
			console.log('m='+n);//20
			console.log('n2='+n2);//19
			n = --n2;
			console.log('m='+n);//18
			console.log('n2='+n2);//18
		</script>
	</head>
	<body>
	</body>
</html>
